Amplifiers that run from an brad bord to a BS2
Hey all,
I need some help. I'm needing to build a amp to make the sound lader or softer. I was also wording if a Class A or a Type A amp would work better for what I'm doing? I have some idea but not to sure. Need help on this.
Ferris!!!!
I need some help. I'm needing to build a amp to make the sound lader or softer. I was also wording if a Class A or a Type A amp would work better for what I'm doing? I have some idea but not to sure. Need help on this.
Ferris!!!!
Comments
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When the going gets weird, the weird turn pro. -- HST
Ferris!!!
Post Edited (Ferris_Bue) : 9/27/2007 4:27:02 PM GMT
http://forums.parallax.com/showthread.php?p=560570
-Stephanie
Ferris!!!!
I think the LM386 is Class AB. It doesn't work very well at 5V and really needs at least 6V.
Class D is used to describe PWM based digital amplifiers.
Ferris!!!!
Ferris!!!!
The gain cap PJ suggested will boost output further -- if you do this I would just make sure that a) you run the circuit from at least 6v (9v is better) and that you check your speaker to see what kind of a wattage it will handle. With the boost cap, don't use one of those cheapo 100mw 8ohm speakers from Radio Shack -- the distortion will be terrible and you may blow the speaker. If memory serves (I am in Jackson Hole right now and don't have the specs in front me), with the boost cap and 9v you will have an amp on the order of 800mw - 1000mw. Without the boost cap, I believe the amp is more on the order of 300-500mw.
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When the going gets weird, the weird turn pro. -- HST
Ferris!!!!
Post Edited (Ferris_Bue) : 10/1/2007 4:20:13 PM GMT
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When the going gets weird, the weird turn pro. -- HST
Can you replace the doc that you put up. Its not leting me see it.
Ferris!!!!
Do you have Reader installed? Can you read PDFs? If not, visit www.adobe.com/products/acrobat/readstep2.html.
Or do a search for LM386 at either Jameco.com or Digikey.com and you'll get links to their posted copies of the spec sheet.
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When the going gets weird, the weird turn pro. -- HST
Amplifiers are usually classified into A, B, and AB.
Class or Type A usually consume more power inorder to produce a more precise signal.
The LM386 has a document that explains it. Without a capacitor between PIN 1 and PIN 8, it will amplify at 20 times the original input. With a 10mf capacitor, it will go up to 200 times.
If you don't need the extra amplification, just leave it out. If you want somewhere between 20 and 200 times, you have to add a resistor in line with the capacitor and an adjustibe resistor is more convienent.
The amplifier will work at +5 volts just fine, but a higher voltage provides more power and possibly a cleaner sound.
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"Everything in the world is purchased by labour; and our passions are the only causes of labor." -- David·Hume (1711-76)········
Post Edited (Kramer) : 10/4/2007 10:21:02 AM GMT
Ferris
Zoot provided a link to the LM386.PDF file. If you can read that, it will help a great deal. It is complete and necessary information.
Regarding Class A, Class B, and Class AB amplifyers - Class A are the best at producing an exact copy of the orignal audio. Class B and Class AB save power by not producing as good a quality reproduction,·sometimes clipping the peaks of the signal.· There are Class C and Class D amplifiers too.
The LM386 is the right chip for a 0.3 watt audio amp for 8 ohm speaker with a +5 to +12volt supply. And the schematic Zoot provided is the right design for a BasicStamp as it includes a low pass filter to make it sound better. You can use a 4 ohm or 16 ohm speaker without trouble.
P.J. Allen copied an example from the LM386.PDF to show you where to put the 10uf capacitor to increase the gain. See the red arrow. I really don't think you need to have Gain = 200 from the BasicStamp. It may just·cause distortion and no real increase in volume. I am trying to build the Gain = 20 set up right now.
If you don't understand basic amplifiers, try Wikipedia for 'amplifier' to get the basics. Or find a good introductory text for electronics.
And I repeat -Type A and Class A are the same thing.
You can do the same thing with a few transistors, but the LM386 makes it so easy.
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"Everything in the world is purchased by labour; and our passions are the only causes of labor." -- David·Hume (1711-76)········
Post Edited (Kramer) : 10/4/2007 10:40:56 AM GMT
Ferris!!!!
I suggested Wikipedia for help with amplifiers, but this is much better.
http://www.tscm.com/NEETS-v08-Amplifiers.pdf
This is what the U.S. Navy uses to train sailor electronic technicians. Fortunately, all the NEETS training manuals are free to the public because there is no copyright protection for U.S. Goverment publications.
If you want all the different topics, go to
http://www.zianet.com/NMAMARS/downloads/neets.htm
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"Everything in the world is purchased by labour; and our passions are the only causes of labor." -- David·Hume (1711-76)········